<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    

    <script>

     
     let a = 100

     console.log(a); //100
     setTimeout(() => {
        console.log(9000); 
    }, 8);
       let pormise = new Promise((resolve,reject)=>{
        console.log('同步');
        resolve(800)  //成功的数据
       })

       //获取到成功的数据
       pormise.then(res=>{
        console.log(res);
       })
      
     function add(){
        
        return 200
     }

     console.log(  add()); //200

     //100  200 800   9000

    </script>
</body>
</html>